1. Field of the Invention
The present invention relates to an electronic cassette used for radiation imaging.
2. Description Related to the Prior Art
Electronic cassettes are widely used in medical radiation imaging, for example, X-ray imaging. The electronic cassette comprises a portable thin box-shaped housing, a flat-panel detector (FPD) accommodated in the housing, and a circuit board. An indirect-conversion type FPD is composed of a scintillator and a sensor panel. The scintillator converts X-rays into visible light. The sensor panel has pixels arranged in two dimensions, and photoelectrically converts the visible light into a signal charge and stores it. A signal processing circuit, a communication circuit for external communication, and the like are formed in the circuit board. The signal processing circuit reads the signal charge from each pixel after the X-ray imaging and outputs the signal charge as X-ray image data. The circuit board is attached to a support substrate.
To perform the X-ray imaging, the electronic cassette may be set in a holder of an X-ray table, placed on a bed, or held by a patient. For example, to image an elderly patient at his/her home or an emergency patient at the site of an accident or a natural disaster, the electronic cassette is used outside of a hospital, without the X-ray table. Hence, it is necessary to reduce the weight of the electronic cassette to improve portability. It is also necessary to improve strength of the electronic cassette to prevent damage.
For example, an electronic cassette disclosed in Japanese Patent Laid-Open Publication No. 2011-247826 has reinforcement members attached to edges of a support substrate to reinforce the support substrate. The reinforcement members suppress deformation of the support substrate in a bending direction.
However, a problem arises from the use of the reinforcement members. The weight of the above-described electronic cassette is increased by the weight of the reinforcement members attached to the support substrate.